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4 Questions You Have about Radiation Therapy

RadiationRAY-DEE-A-SHUN TREET-MINT — High energy waves used to treat cancer in a specific area of the body is a pretty common type of local treatmentLOW-COAL TREET-MINT — Techniques targeting a single area of the body to eliminate or control a cancer for many different kinds of cancers. So, it’s likely you’ve heard about it at some point. However, you might be more familiar with its side effects than how it works.

So to fill in the gaps, let’s go over how radiation works to kill cancer and why it’s an effective choice of treatment in many cases. Before we dive into the details, let’s start with its definition.

Radiation uses high-energy waves to kill cancer cells in a specific area of the body.1

Alright, time to dig deeper.

1. What is a Target of RadiationThe area where doctors direct the radiation waves in order to control or kill cancer cells?

Think back to when you were younger and played with flashlights in the dark. The flashlight only allowed you to see a small area. This lit up area is similar to what doctors call a target of radiation in the body.

Like the light waves created by a flashlight, radiation waves can only be directed at a small area. For example, breast cancerBREST CAN-SIR — An abnormal growth that originates from breast tissue radiation typically targets the breast and underarm region. The target(s) for radiation for your treatment will depend on your type of cancer, stage, specific case, and other factors.


2. How Does Radiation Kill Cancer Cells?

Radiation works because cancer cells “move at a different speed than normal cells. What do we mean by that? The speed of cells refers to how quickly they duplicate.

While most normal cells replicate slowly or not at all, cancer cells replicate really quickly. This is usually because the cancer cells have mutationsMU-TAY-SHUN — A change in DNA that can lead to or cause cancer that drive the cells to multiply abnormally fast.

Radiation takes advantage of this difference pretty effectively, destroying the cancer cells and temporarily injuring normal cells. How?

Radiation works by passing waves through targeted tissueTISH-YOU — The accumulation of cells that make up parts of the body, like organs to damage the DNADEE-OX-SEE-RYE-BOW-NEW-CLAY-IK AH-SID — The blueprint of a cell that controls the function of all components within the cell of a cellSEL — One of the most basic components of all living things that together form the entire body and contains many smaller parts that guide its function. This stops the cells from working and multiplying.1 Since cancer cells are duplicating more quickly, they’re actively using their DNA, making them more vulnerable and exposed to the effects of the radiation.

So, when the radiation waves hit a replicating cancer cell, it’s injured beyond repair. However, normal cells are only temporarily injured by the radiation and are able to recover after some time.

3. When Is Radiation Used?

Radiation can be used to treat many different cancers and in various ways. It’s really good at killing most types of cancer cells when they’re grouped in one location.

Here are some of the more common situations in which radiation is used.
  • It can cure some cancers by itself.
  • It can be used by itself to control a cancer-related problem like pain (palliative radiationPA-LEE-UH-TIV RAY-DEE-A-SHUN — Radiation treatment that is given to control symptoms caused by the cancer (not to cure the cancer)).
  • It might be used with systemic treatmentsSIS-TEM-IK TREET-MINT — Techniques targeting the whole body to eliminate or control a cancer, like chemotherapyKEY-MOW-THAIR-AH-PEE — Medication used to treat cancer, making the radiation work even better (concurrent chemotherapy and radiationWhen chemotherapy and radiation treatments are both given during the same period of time (overlap))
  • It may be used after surgerySIR-JER-REE — The physical removal of something (like a tumor) to kill any remaining cells that might have been left behind.

4. What are the Types of Radiation?

There are many different types of radiation used today, but external beam radiationEX-TURN-NOL BEAM RAY-DEE-A-SHUN — High energy waves used to treat an area of the body is the most common type.

External beam radiation directs high-energy rays from outside the body at a tumorTOO-MER — An abnormal growth in the body inside the body. It's easy to remember—external (outside) beam(rays) radiation. External beam radiation is typically given over many days to weeks.


Stereotactic radiationSTAIR-E-O-TAK-TIC RAY-DEE-A-SHUN — A very precise radiation technique that delivers high doses of radiation to a very targeted area is a type of radiation that delivers a very high dose of radiation over several days (sometimes even a single day) to kill the targeted cancer. Stereotactic radiation can only treat a small area, but it usually only has a few side effects and only causes minimal damage to the nearby tissue. Stereotactic radiation is becoming more and more common and is especially good at treating tumors in the brain.

Some other types of radiation include brachytherapyBRAH-KEE-THAIR-A-PEE — High doses of high energy waves delivered through an implant directly into tissue (a form of local radiation) and selective internal radiation therapySEL-EC-TIV IN-TURN-OL RAY-DEE-A-SHUN THAIR-AH-PEE — A directed radiation technique that delivers high doses of radiation to a targeted organ or tumor, typically through the bloodstream (SIRT) (also known as Y90 radioembolization).

  1. Radiation Therapy for Cancer. National Cancer Institute. https://www.cancer.gov/about-cancer/ treatment/types/ radiation-therapy/ radiation-fact-sheet. Accessed February 14, 2017.
  2. Early Breast Cancer Trialists’ Collaborative Group (EBCTCG), Darby S, McGale P, et al. Effect of radiotherapy after breast-conserving surgery on 10-year recurrence and 15-year breast cancer death: Meta-analysis of individual patient data for 10 801 women in 17 randomized trials. The Lancet. 2011;378(9804):1707–1716. doi:10.1016/s0140-6736(11)61629-2.
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